# Define here the models for your spider middleware
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html
from random import random

from scrapy import signals
import requests

from .settings import USER_AGENT_LIST,  PROXY_HOST
from scrapy.downloadermiddlewares.useragent import UserAgentMiddleware

# useful for handling different item types with a single interface
from itemadapter import is_item, ItemAdapter


class RandomProxyMiddleware:
    def __init__(self, proxys, proxy_host):
        self.proxy_host = proxy_host
        self.proxys = proxys

    @classmethod
    def from_crawler(cls, crawler):
        settings = crawler.settings
        return cls(proxys=settings.get("PROXIES"), proxy_host=settings.get("PROXY_HOST"))

    def get_random_proxy(self):
        # if self.proxys:
        #     proxy = random.choice(self.proxys)
        #     return proxy
        try:
            response = requests.get(self.proxy_host,verify=False)
            if response.status_code == 200:
                proxy = response.text
                return proxy
        except requests.ConnectionError:
            return ""

    def process_request(self, request, spider):
        if not request.meta.get("retry_times", 0):
            proxy = self.get_random_proxy()
            print(proxy)
            if proxy:
                uri = "http://{proxy}".format(proxy=proxy)
                auth=('test', '123456')
                spider.logger.debug("使用代理 " + proxy)
                request.meta["proxy"] = uri
                # request.headers

class TutorialSpiderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, or item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Request or item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class TutorialDownloaderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        ua = random.choice(USER_AGENT_LIST)
        if ua:
            request.headers.setdefault("User-Agent", ua)


    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)
